Last Updated Jun 1, 2009 3:20 AM EDT
What happened subsequently is described in recent New Yorker article Don't! Mischel, while asking his daughters about the progress of their peers, noticed that it was the ones who were in the ten percent who were getting better scholastic and social results. This led Mischel and his colleagues to carry out full-scale studies and conclude the best predictor of success was not IQ but the ability to control emotional impulses.
It was initially thought that the children's ability to wait depended on how badly they craved the marshmallow. However all the children were cravers. What determined the level of self control was the ability of the child to distract themselves and stop focusing on the marshmallow. The key is to avoid thinking about the marshmallow in the first place. This skill is known as metacognition, or thinking about thinking. It is what allows people to outsmart their shortcomings. For example, Mischel demonstrated that by the simple mental trick of thinking that the candy is only a picture, and surrounding it with an imaginary frame, that children, who previously would pounce on the marshmallow in seconds, would easily wait the 15 minutes.
Don't is a highly recommended read and contains a number of new ideas. However the core concept is that the key to success is self-control. Teaching our children, and ourselves, to develop self-control as a habit is perhaps the most useful thing we can do. With apologies to Aristotle: "Self-Control is an art won by training and habituation. We are what we repeatedly do. Self-Control, then, is not an act but a habit."